1. Technical Field
The present invention relates to an apparatus and method for controlling exhaust pressure in a semiconductor manufacturing system. Controlling exhaust pressure in a semiconductor system may increase the number of times a valve is opened and/or closed. A valve may include one or more additional valves, which may be opened and closed selectively, and which may operate at a cross-section of an exhaust hole.
2. Discussion of the Related Art
Some example considerations of semiconductor technology may include integration, density, performance and large-diameter wafer design. To increase integration and/or produce performance semiconductor products, it may be necessary to satisfy specific manufacturing conditions. The amount of pressure, the level of temperature and/or the amount of gas are some examples of semiconductor manufacturing considerations.
Semiconductor manufacturing may include an exhaust system, for example, a chamber may be connected with a vacuum pump via a connecting pipe. Based on this configuration the pipe may be selectively opened and/or closed, which may occur after a gas is discharged into the chamber. A valve may be installed between the process chamber and the vacuum pump for controlling the discharge gas flow through the pipe. The valve may act to reduce or increase the amount of pressure formed in the chamber by regulating the flow of exhaust gas.
In a conventional configuration, a chamber may control the pressure and the amount of exhaust gas. The chamber may, for example, provide a bypass path at one side of a main exhaust path of a pipe, and/or provide a bypass path with a control valve. The control valve may be separate from another valve of the main exhaust path of the pipe, and/or the two valves may be in a series configuration in the main exhaust path.
A conventional configuration may also provide a throttle valve disposed between a reactor and a mechanical booster pump. The throttle valve and the mechanical booster pump may be connected, and may operate to control the amount of pressure in the reactor.
FIGS. 1-2 illustrates a conventional valve used for regulating and/or controlling the exhaust gas flow in a pipe. As shown, the valve may be disposed between the reactive chamber and the vacuum pump. The valve may open and/or close via the vacuum pressure of the vacuum pump, thus the pressure in the reactive chamber may be controlled. For a wafer, for example having a large diameter, the internal volume of a reactive chamber and the size of a pumping port may be larger to control the flow of exhaust gas.
FIG. 3 illustrates a rate of change for the open area of an exhaust hole based on the distance a valve is moved in a valve port, according to the conventional configurations of FIGS. 1-2. It may be noted that the pressure of the reactive chamber may change abruptly when a closed valve is opened.
If the amount of pressure in the reactive chamber changes abruptly, then a control mechanism may not perform accurately. The control mechanism may control the degree of openness of the valve based on the amount of pressure in the reactive chamber. Therefore, controlling the degree of openness of the valve may be difficult.
The vacuum pump and/or the valve may be controlled based on the amount of pressure in the reactive chamber. If the amount of pressure in the reactive chamber is not accurately measured, then it may be difficult to accurately control the pressure in the reactive chamber. The inability to properly control the pressure in the reactive chamber may result in instability, which may lead to reduced system performance and/or of the product yield.